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  2. Internal structure of Earth - Wikipedia

    en.wikipedia.org/wiki/Internal_structure_of_Earth

    Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 19% of Earth's radius [0.7% of volume] or 70% of the Moon 's radius. [32][33] The inner core was discovered in 1936 by Inge Lehmann and is generally composed primarily of iron and some nickel.

  3. Earth's inner core - Wikipedia

    en.wikipedia.org/wiki/Earth's_inner_core

    Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 20% of Earth’s radius or 70% of the Moon 's radius. [1][2] There are no samples of Earth's core accessible for direct measurement, as there are for Earth's mantle. [3]

  4. Hollow Earth - Wikipedia

    en.wikipedia.org/wiki/Hollow_Earth

    The Hollow Earth is a concept proposing that the planet Earth is entirely hollow or contains a substantial interior space. Notably suggested by Edmond Halley in the late 17th century, the notion was disproven, first tentatively by Pierre Bouguer in 1740, then definitively by Charles Hutton in his Schiehallion experiment around 1774.

  5. Earth - Wikipedia

    en.wikipedia.org/wiki/Earth

    Earth is the third planet from the Sun and the only astronomical object known to harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust.

  6. Van Allen radiation belt - Wikipedia

    en.wikipedia.org/wiki/Van_Allen_radiation_belt

    The inner Van Allen Belt extends typically from an altitude of 0.2 to 2 Earth radii (L values of 1.2 to 3) or 1,000 km (620 mi) to 12,000 km (7,500 mi) above the Earth. [ 4 ] [ 16 ] In certain cases, when solar activity is stronger or in geographical areas such as the South Atlantic Anomaly , the inner boundary may decline to roughly 200 km ...

  7. Satellite imagery - Wikipedia

    en.wikipedia.org/wiki/Satellite_imagery

    The first images from space were taken on the sub-orbital V-2 rocket flight launched by the US on October 24, 1946. Satellite image of Fortaleza.. Satellite images (also Earth observation imagery, spaceborne photography, or simply satellite photo) are images of Earth collected by imaging satellites operated by governments and businesses around the world.

  8. Pale Blue Dot - Wikipedia

    en.wikipedia.org/wiki/Pale_Blue_Dot

    Pale Blue Dot is a photograph of Earth taken on February 14, 1990, by the Voyager 1 space probe from an unprecedented distance of approximately 6 billion kilometers (3.7 billion miles, 40.5 AU), as part of that day's Family Portrait series of images of the Solar System. In the photograph, Earth's apparent size is less than a pixel; the planet ...

  9. Earth's magnetic field - Wikipedia

    en.wikipedia.org/wiki/Earth's_magnetic_field

    The Earth and most of the planets in the Solar System, as well as the Sun and other stars, all generate magnetic fields through the motion of electrically conducting fluids. [54] The Earth's field originates in its core. This is a region of iron alloys extending to about 3400 km (the radius of the Earth is 6370 km).